(Adds background)

CAIRO, May 16 (Reuters) - An Egyptian court on Saturday outlawed popular soccer fan clubs known as "Ultras" which have played a role in political demonstrations and violence since Egypt's 2011 uprising, the state news agency said.

The reasons for the ruling, which can be appealed, were not immediately clear. But the decision risks sparking an anti-government backlash among the thousands of highly politicised young men nationwide who claim membership.

Relations between the Ultras and security forces have been tense for the past four years after the fans played a key role in the 18 days of street protests that toppled veteran autocrat Hosni Mubarak.

Soccer matches are often a flashpoint for violence in Egypt where 72 fans were killed at a match in Port Said in February 2012. Since then Egypt has curbed the number of people allowed to attend, and supporters have often tried to storm stadiums they are banned from entering.

Most recently, members of the Ultras were charged, alongside Muslim Brotherhood supporters, with carrying out violence outside a Cairo stadium in March. ID:nL6N0WJ25Q

(Reporting By Stephen Kalin and Omar Fahmy; Editing by Michael Georgy and Dominic Evans) ((stephen.kalin@thomsonreuters.com; +20 101 584 1700; Reuters Messaging: stephen.kalin.thomsonreuters.com@reuters.net))

Keywords: EGYPT COURT/SOCCER